Gas Extractions Under Pressure? How to Take Some of the Steam out of Gas Extraction
An innovative new liquid gas extraction technology— requires only moderate pressure and leads to improved efficiencies and performance. It offers significant cost savings in small batch applications.
Dimethyl ether (DME), also known as methoxymethane, is an organic compound that exists as a non–toxic gas under atmospheric conditions. It is the simplest ether and can be derived from many sources, including renewable biomass, natural gas and coal. The new process from SPX applies DME to extract organic material and requires the use of only moderate pressure. DME is commonly used as an environmentally friendly propellant in aerosol canisters and is being increasingly utilized as an alternative fuel solution. It is now approved as an extraction agent for animal-origin proteins in Europe and approval procedures for further food products are in progress.
DME Requires Lower Pressure
Traditionally, liquid gas extraction is conducted with carbon dioxide (CO2), but this requires pressures of 150 – 500 bar. DME, however, liquefies at approximately five bar. This much lower pressure requirement and rating significantly reduces the cost of the equipment required as well as simplifies installation requirements.
The DME liquid gas is pumped from a storage tank through the extractor vessel which contains the solid raw material. The extracting agent can be fed through the extraction vessel from either the top or the bottom and the solvent is circulated between tanks until the extraction process is completed. The temperature control of the solvent is managed by means of heat exchangers.
Also Helpful for Solvents like Propane or Butane
When the extraction step is complete, the liquid solvent containing the extracted substances is then transferred to a separator where the expanded volume reduces the pressure and, because of its low boiling point (-28°C), the gas is flashed off. It leaves through the top of the separator to a condenser and is pumped as a liquid back to a second storage tank for recycling. Besides DME, other solvents with similar boiling points may be used on the pilot plant, such as propane or butane.